Coil encapsulation with thermoplastic resins

Encapsulation with thermoplastic resins is becoming an increasingly attractive alternative to thermosets in the protection of coils subjected to harsh operating environments. Coil-based sensors, solenoids, transformers, toroids and motors are all produced in large volumes today and encapsulated in thermoplastics to lower manufacturing costs, reduce lead wire leakage and eliminate the volatile organic compounds (VOC) commonly found in thermoset processing. This paper provides a general overview of thermoplastic material requirements and encapsulation tips. It also reviews the high performance thermoplastic polymer resins used in coil encapsulation and the reasons for their increasing use, presents some of the more promising applications and outlines UL and automotive requirements for encapsulated coil materials